According
to the Organization of Petroleum Exporting Countries (OPEC),
the world proven crude oil reserves stood at 1,074,850 million
barrels* (about 153 billion
tonnes) at the end of 2001. Close to 79 per cent of these
reserves (845,421 million barrels) were in the eleven OPEC
countries (Algeria, Indonesia, Iran, Iraq, Kuwait, Libya,
Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and
Venezuela).

At
the end of 2001, Saudi Arabia had the largest of these proven
reserves (262,697 million barrels), followed by Iraq, Iran,
United Arab Emirates, and Kuwait, with together about 400,000
million barrels). OPEC estimates that the oil reserves in
its member countries will last for another 80 years (at
the current rate of production), while the reserves of non-OPEC
oil producers (e.g., in the Northeast Atlantic) might last
less than another 20 years.

See
also International Energy Agency (IEA) and other information
sources on world oil reserves.

GLOBAL
OIL PRODUCTION

At
the end of 2001, the world oil production was about 9.3
million tonnes per day (OPEC). At
this time, Saudi Arabia was also the largest of the producer
with almost 7.9 million barrels (approx. 1.3 million tonnes)
per day, followed by Russian Federation, United States,
Iran and China. The world's biggest producers of oil are
Saudi Arabia, the United States, the Russian Federation,
Iran, Mexico, Venezuela, Norway, China, Canada and the United
Kingdom.

According
to a report published in 2002 by the National Research Council
(NRC) of the U.S. National Academy of
Sciences, the world oil production was 11 million tonnes
per day in 2000.

In
2000, the world consumption of oil, according to the reference
case of OPEC's World Energy Model, was 76 million barrels
per day (close to 11 million tonnes). The forecast was an
increase in consumption to almost 91 million barrels per
day in 2010 and to 103 million barrels a day in 2020. According
to the U.S. Energy Information Administration (EIA),
the global consumption of petroleum increased from 9.3 to
11.7 million tonnes per day during the period 1985-2000,
an increase of over 25 per cent.

Offshore
oil production accounts for about 30 per cent of the total
world oil production, and offshore gas production for about
half of the world production of natural gas.

According
to the NRC report, there were about 8,300 fixed or floating
offshore platforms worldwide in 1999. The UNEP Offshore
Oil and Gas Environment Forum (OEF) gives
these figures: more than 6,500 offshore oil and gas installations
worldwide, about 4,000 of which in the U.S. Gulf of Mexico,
950 in Asia, 700 in the Middle East and 400 in Europe.

OIL
ENTERING THE MARINE ENVIRONMENT

According
to the NRC report, about 1.3 million tonnes of oil (as best
estimate) enter the sea worldwide each year from all sources
 natural seepage, extraction, transport, and consumption.

However,
the range of estimated worldwide input of oil (petroleum
hydrocarbons) into the oceans is wide, from a possible 470,000
tonnes to a possible 8.4 million tonnes per year.

The
Council has lowered its estimate of the total input of oil
into the marine environment considerably since its 1985
report, when the estimated was 3.2 million tonnes per year.
As pointed out in the 2002 report: "This has probably
resulted because the databases and computational methods
have improved significantly since the 1985 NRC report, and
there have been worldwide efforts to stem pollution of the
world's oceans".

In
1993, the Joint Group of Experts on the Scientific Aspects
of Marine Environmental Protection (GESAMP),
estimated the total annual global input of oils (hydrocarbons)
into the marine environment to be 2.3 million tonnes.

For
detailed figures of estimated annual discharges from different
sea-based and land-based sources: >>> Sources.

*
1 barrel = 42 American gallons or 35 British imperial gallons
= 159 litres. In round figures: 79 barrels = 1 ton of
oil, depending on the type of oil. Or: 294 American gallons
= 1 ton of oil (ranging from 256 American gallons per ton of
heavy distillate to 333 American gallons per ton of gasoline,
with crude oil at 272 American gallons per ton).

IEA:
World
Energy Outlook. International Energy Agency (IEA). See
also "World Energy Investment Outlook", which
builds on the World Energy Outlook and presents a
detailed analysis of the global energy investment challenge.

IPIECA
and OGP: Industry
as a partner for sustainable development: Oil and gas report.
A status report prepared by the oil and gas industry as
input to the 2002 World Summit in Johannesburg (WSSD); the
first such global review of this sector. Produced jointly
by International Petroleum Industry Environmental Conservation
Association (IPIECA) and OGP.

GESAMP: "Impact
of oil and related chemicals and wastes on the marine environment".
GESAMP Report 50, 1993. Not available online, but the figures
referred to can also be found in the online article "Oil
pollution of the sea".

The
impact of marine pollution. Report (1980) by Douglas J.
Cuisine and John P. Grant. Table published on the UN
Atlas of the Oceans web site.

OEF:
Offshore
Oil and Gas Environment Forum: Emissions (OEF). A UNEP
web site intended as a "medium to locate and disseminate
environmental information concerning the sustainable development
of the offshore oil and gas industry".